Snowmobile having front tracks with brakes

ABSTRACT

A central endless drive track is disposed below the seat of a snowmobile. At least two left wheels are operatively connected to a left track frame disposed forwardly of the seat. A left track engages the left wheels. A left brake is connected to the left track frame and selectively engages one of a first left wheel and the left track to brake the left track. At least two right wheels are operatively connected to a right track frame disposed forwardly of the seat. A right track is disposed around the right wheels. A right brake is connected to the right track frame and selectively engages one of a first right wheel and the right track to brake the right track. A brake lever causes the left and right brakes to brake the left and right tracks respectively.

CROSS-REFERENCE

The present application is a continuation of U.S. patent applicationSer. No. 12/626,809 filed on Nov. 27, 2009, which claims priority toUnited States Provisional Application No. 61/118,496 filed on Nov. 28,2008, the entirety of both of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to snowmobiles having front tracks withbrakes.

BACKGROUND

A conventional snowmobile is propelled by a rear track that is driven byan engine disposed on the snowmobile. One or two front skis are used tosteer the snowmobile. The skis are designed to have a smooth glidingsurface in contact with the snow, to provide flotation on the snow andreduce friction while the snowmobile is moving.

When a rider attempts to brake the snowmobile, a braking force isapplied to some part of the power transmission between the engine andthe rear track, usually to one of the rotating shafts. This brakingforce causes the rotation of the rear track to slow or stop, which inturn creates drag between the rear track and the snow, reducing thespeed of the snowmobile.

However, during braking, a portion of the weight of the snowmobile istransferred from the rear track to the front skis. As a result, the reartrack generates less friction, and slowing the rear track is lesseffective in reducing the speed of the snowmobile. In addition, thefront skis do not assist in braking, despite bearing an increasedproportion of the weight of the snowmobile, because they are designed tofloat above the snow and generate as little friction with the snow aspossible. As such, while conventional braking systems are sufficient formost snowmobiles, it may be desirable in some snowmobiles to provideadditional braking.

Therefore, there is a need for a snowmobile having a braking systemproviding braking in addition to the braking provided by the rear track.

SUMMARY OF THE INVENTION

It is an object of the present invention to ameliorate at least some ofthe inconveniences present in the prior art.

It is also an object of the present invention to provide a snowmobilehaving front endless tracks provided with brakes.

In one aspect, the invention provides a snowmobile comprising a mainframe having a longitudinal centerline. A seat is operatively connectedto the main frame. A central endless drive track is disposed along thelongitudinal centerline below the seat and operatively connected to themain frame. A main motor is disposed on the main frame and operativelyconnected to the central endless drive track to drive the centralendless drive track. A left track frame is disposed forwardly of theseat and to the left of the longitudinal centerline. The left trackframe is operatively connected to the main frame. At least two leftwheels are operatively connected to the left track frame. The at leasttwo left wheels include a first left wheel. A left endless track engagesthe at least two left wheels. A left brake is connected to the lefttrack frame and selectively engages one of the first left wheel and theleft endless track to brake the left endless track. A right track frameis disposed forwardly of the seat and to the right of the longitudinalcenterline. The right track frame is operatively connected to the mainframe. A least two right wheels are operatively connected to the righttrack frame. The at least two right wheels include a first right wheel.A right endless track engages the at least two right wheels. A rightbrake is connected to the right track frame and selectively engages oneof the first right wheel and the right endless track to brake the rightendless track. A handlebar is operatively connected to the left andright track frames to steer the left and right endless drive tracks. Abrake lever is disposed on the handlebar and operatively connected tothe left and right brakes to cause the left and right brakes to brakethe left and right endless tracks respectively.

In a further aspect, the central endless drive track has a roundedlateral profile.

In a further aspect, the left and right endless tracks each have arounded lateral profile.

In a further aspect, the central endless drive track, and left and rightendless tracks each have a rounded lateral profile.

In a further aspect, the at least two left wheels and the at least tworight wheels are idler wheels.

In a further aspect, at least one of the at least two left wheels is aleft driving wheel. At least one of the at least two right wheels is aright driving wheel. A loft motor is operatively connected to the leftdriving wheel for driving the left driving wheel. A right motor isoperatively connected to the right driving wheel for driving the rightdriving wheel.

In a further aspect, the left and right motors arc one of electricmotors and hydraulic motors.

In a further aspect, the left brake selectively engages the left drivingwheel. The right brake selectively engages the right driving wheel.

In a further aspect, the left motor is disposed to the right of the leftdriving wheel and the left brake is disposed to the left of the leftdriving wheel. The right motor is disposed to the left of the rightdriving wheel and the right brake is disposed to the right of the rightdriving wheel.

In a further aspect, the left brake selectively engages one of the atleast two left wheels. The right brake selectively engages one of the atleast two right wheels.

In a further aspect, the left brake selectively engages an inner side ofthe left endless drive track. The right brake selectively engages aninner side of the right endless drive track.

In a further aspect, a left swing arm operatively connects the lefttrack frame to the main frame. A right swing arm operatively connectsthe right track frame to the main frame.

In a further aspect, the left track frame is pivotally connected to theleft swing arm about a generally vertical left steering axis. The righttrack frame is pivotally connected to the right swing arm about agenerally vertical right steering axis.

For purposes of this application, directional terms such as “forwardly”,“rearwardly”, “right” and “left” are defined with respect to a forwarddirection of travel of the snowmobile, and should be understood as theywould be understood by a rider sitting on the snowmobile in a normalriding position.

Embodiments of the present invention each have at least one of theabove-mentioned objects and/or aspects, but do not necessarily have allof them. It should be understood that some aspects of the presentinvention that have resulted from attempting to attain theabove-mentioned objects may not satisfy these objects and/or may satisfyother objects not specifically recited herein.

Additional and/or alternative features, aspects, and advantages ofembodiments of the present invention will become apparent from thefollowing description, the accompanying drawings, and the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, as well as otheraspects and further features thereof, reference is made to the followingdescription which is to be used in conjunction with the accompanyingdrawings, where:

FIG. 1 is a perspective view, taken from a front, left side, of asnowmobile according to the present invention;

FIG. 2 is a top plan view of the snowmobile of FIG. 1;

FIG. 3 is a front elevation view of the snowmobile of FIG. 1;

FIG. 4 is a left side elevation view of a left front track of thesnowmobile of FIG. 1 according to a first embodiment;

FIG. 5 is a schematic cross-sectional view of the left front track ofFIG. 4, taken along the line 5-5 in FIG. 4;

FIG. 6 is a left side elevation view of a left front track of thesnowmobile of FIG. 1 according to a second embodiment;

FIG. 7 is a schematic cross-sectional view of the left front track ofFIG. 6, taken along the line 7-7 in FIG. 6;

FIG. 8 is a left side elevation view of a left front track of thesnowmobile of FIG. 1 according to a third embodiment;

FIG. 9 is a schematic cross-sectional view of the left front track ofFIG. 8, taken along the line 9-9 in FIG. 8;

FIG. 10 is a left side elevation view of a left front track of thesnowmobile of FIG. 1 according to a fourth embodiment; and

FIG. 11 is a schematic cross-sectional view of the left front track ofFIG. 10, taken along the line 11-11 in FIG. 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1-3, a snowmobile 10 will be described. Thesnowmobile 10 has a main frame 12 supporting a seat 14 for a rider.Footrests 16 are provided on left and right sides of the longitudinalcenterline 18 of the snowmobile 10 the supporting the feet of the rider.A central endless drive track 20 is disposed toward the rear of thesnowmobile 10, along the longitudinal centerline 18 and generally belowthe seat 14. Wheels 22 are disposed inside the track 20. The wheels 22are connected to the main frame 12 via a suspension assembly 24. A guard26 disposed above the track 20 is connected to the suspension assembly24. The track 20 has a rounded lateral profile (best seen in FIG. 3). Amotor 28 (shown schematically), preferably an internal combustionengine, is supported on the frame 12 and operatively connected to thetrack 20 via a transmission not shown) to drive the track 20. A cowling30, made of multiple parts encloses the motor 28, thereby protecting themotor 28 and also making the snowmobile 10 more aesthetically pleasing.

A front suspension system consists of left and right swing arms 32L, 32Rpivotably connected to the frame 12 such that they pivot independentlyabout a front suspension axis 34. A torsional spring (not shown) and atorsional damper (not shown) operatively connected between each swingarm 32L, 32R and the frame 12. It is contemplated that the frontsuspension system may alternatively have a linear spring and a lineardamper. Left and right track holders 36L, 36R are pivotally connected tothe from ends of the left and right swing arms 32L, 32R, respectively,about generally vertical steering axes 38L, 38R. Left and right trackframes 40L, 40R are pivotally connected to the left and right trackholders 36L, 36R, respectively, about generally horizontal transverseaxes 42L, 42R. Left and right wheels 44L, 44R are mounted to theirrespective track frames 40L, 40R. The wheels 44L, 44R are shown ashubless wheels supported by bearings (not shown), however it iscontemplated that conventional wheels ma alternatively be used. It isfurther contemplated that two wheels, or more than three wheels, may beprovided on each track frame 40L, 40R, and that one or more of thewheels 44L, 44R may be driving wheels instead of idler wheels. Left andright endless tracks 46L, 46R are disposed around their respectivewheels 44L, 44R. The wheels 44L, 44R support the respective tracks 46L,46R and maintain the desired shape and tension of the tracks 46L, 46R.As can be seen, the endless tracks 46L, 46R are disposed forwardly ofand to either sides of the seat 14. The left and right endless tracks46L, 46R each have a rounded lateral profile (best seen in FIG. 3). Thepivotal connections of the track frames 40L, 40R to the track holders36L, 36R about axes 42L, 42R, allow the tracks 46L, 46R to moreeffectively follow the ground when the snowmobile 10 is in motion. Theleft and right track holders 36L, 36R are operatively connected to ahandlebar 48 disposed generally forwardly of the seat 14, such that therider can rotate the handlebar 48 to pivot the left and right endlesstracks 46L, 46R about the steering axes 38L, 38R to steer the snowmobile10. A brake lever 50 is disposed on the handlebar 48 for braking therear track 20 of the snowmobile 10 in a conventional manner, a well asfor braking the front tracks 46L, 46R in it manner that will bediscussed below in further detail. It is contemplated that two brakelevers 50 may be provided, in which case one brake lever 50 would causebraking of the rear track 20 and the other brake lever 50 would causebraking of the front tracks 46L, 46R. It is further contemplated thatthe rear track 20 of the snowmobile 10 may not be provided with a brake,in which ease the brake lever 50 would be used only to brake the fronttracks 46L, 46R as the sole method of braking the snowmobile 10.

The braking of the left front track 46L will now be described accordingto a number of embodiments. In all of these embodiments, it should beunderstood that the right front track 46R and the right front trackframe 40R are essentially mirror images of the left front track 46L andthe left front track frame 40L, and the braking of the right front track46R functions in a similar manner, and as such they will not beseparately described.

Referring to FIGS. 4 and 5, the braking of the left front track 46L willbe described according to a first embodiment. A brake assembly 400includes a brake caliper 402 mounted to the track frame 40L. The caliper402 receives a portion of the outer middle wheel 44L therein. A similarcaliper (not shown) is mounted on the Inner middle wheel 44L. The brakecaliper 402 is fluidly connected to a master cylinder 403 mounted on thebrake lever 50 via the hydraulic line 404. The master cylinder 403 isoperatively connected to the brake lever 50, such that when the rideractuates the brake lever 50, the master cylinder 403 causes the caliper402 to press a pair of brake pads 408 against the middle wheel 44L,reducing the rotational speed of the middle wheel 44L. The engagementbetween the middle wheel 44L and the track 46L causes a reduction of therotational speed of the track 46L. In this manner, the brake assembly400 supplements the braking force of the rear track 20 to slow theforward motion of the snowmobile 10. It is further contemplated that thebrake assembly 400 may additionally or alternatively be applied to thefront or rear wheels 44L. It is further contemplated that the brakelever 50 could alternatively be connected to the brake assembly 400 viaa mechanical linkage such as to cable, in which case the master cylinder403 could be omitted.

Referring to FIGS. 6 and 7, the braking of the left front track 46L willbe described according to a second embodiment. A brake assembly 600includes a pair of brake pads 602 mounted to the frame 40L inside therear wheel 44L via the support arms 604. An inward projection of therear wheel 44L acts as a brake disk 606 that is received between thebrake pads 602. A spring 608 biases the brake pads 602 away from thedisk 606. An actuator cable 610 is operatively connected to the brakelever 50, such that when the rider actuates the brake lever 50, inaddition to a braking force being applied to the rear track 20, thecable 610 urges the brake pads 602 toward the disk 606 against thebiasing force of the spring 608. The friction between the brake pads 602and the disk 606 reduces the rotational speed of the rear wheel 44L, Theengagement between the wheel 44L and the track 46L causes a reduction ofthe rotational speed of the track 46L. In this manner, the brakeassembly 600 supplements the braking force of the rear track 20 to slowthe forward motion of the snowmobile 10. It is contemplated that thebrake assembly 600 may additionally or alternatively be applied to thefront or middle wheels 44L.

Referring to FIGS. 8 and 9, the braking of the left front track 46L willbe described according to a third embodiment. A brake assembly 800includes a brake pad 802 supported on a linkage 804 that is pivotablymounted to the frame 40L about pivot axes 805, 806. One arm 807 of thelinkage is actuated by a cable 808 that is operatively connected to thebrake lever 50, such that when the rider actuates the brake lever 50,the linkage 804 urges the brake pad 802 against the inner side of thetrack 46L. The engagement between the brake pad 802 and the track 46Lreduces the rotational speed of the track 46L. In this manner, the brakeassembly 800 supplements the braking force of the rear track 20 to slowthe forward motion of the snowmobile 10.

Referring to FIGS. 10 and 11, the braking of the left front track 46Lwill be described according to a fourth embodiment. In this embodiment,the middle wheels 44L are replaced by a single driving wheel 1002 inengagement with the track 46L and coupled to a motor 1004 (FIG. 11) inthe form of an electric motor or a hydraulic motor. The motor 1004 ispowered by a suitable power source 1006 (shown schematically) of thesnowmobile 10. If the motor 1004 is an electric motor, the power source1006 is electrical system of the snowmobile 10. If the motor 1004 is ahydraulic motor, the power source 1006 is a hydraulic pump and valveassembly of the snowmobile 10. The motor 1004 drives the wheel 1002 torotate about the axis 1007, thereby driving the track 46L to assist therear track 20 in propelling the snowmobile 10. A brake assembly 1000includes a brake disk 1008 coupled to the driving wheel 1002 such thatthe brake disk rotates about the axis 1007. A brake caliper 1010 (FIG.10), similar to the caliper 402 of FIG. 4, is operatively connected tothe brake lever 50 and causes brake pads 1012 to selectively engage thebrake disk 1008 in substantially the same manner as the caliper 402 tobrake the track 46L. In this manner, the brake assembly 1000 supplementthe braking force of the rear track 20 to slow the forward motion of thesnowmobile 10. It is contemplated that the brake assembly 1000 mayadditionally or alternatively be applied to the froth or rear wheels44L.

Referring to FIG. 11, showing a cross-section of the left track 46L, theleft motor 1004 is disposed to the right of the left driving wheel 1002,and the left brake disk 1008 is disposed to the left of the left drivingwheel 1002. It should be understood that the right track 46R is arrangedin a mirror image of this arrangement, such that the right motor 1004 isdisposed to the left of the right driving wheel 1002, and the rightbrake disk 1008 is disposed to the right of the right driving wheel1002. Other arrangements are contemplated, such as disposing each motor1004 laterally outwardly of the respective wheel 1002 and each brakedisk 1008 laterally inwardly of the respective wheel.

Modifications and improvements to the above-described embodiments of thepresent invention may become apparent to those skilled in the art. Theforegoing description is intended to be exemplary rather than limiting.The scope of the present invention is therefore intended to be limitedsolely by the scope of the appended claims.

1. A snowmobile comprising: a main frame having a longitudinalcenterline; a seat operatively connected to the main frame; a centralendless drive track disposed along the longitudinal centerline below theseat and operatively connected to the main frame; a main motor disposedon the main frame and operatively connected to the central endless drivetrack to drive the central endless drive track; a left track framedisposed forwardly of the seat and to the left of the longitudinalcenterline, the left track frame being operatively connected to the mainframe; a left endless track supported by the left track frame; a leftbrake connected to the left track frame and selectively engaging theleft endless track to brake the left endless track; a right track framedisposed forwardly of the seat and to the right of the longitudinalcenterline, the right track frame being operatively connected to themain frame; a right endless track supported by the right track frame; aright brake connected to the right track frame and selectively engagingthe right endless track to brake the right endless track; a handlebaroperatively connected to the left and right track frames to steer theleft and right endless tracks; a brake lever disposed on the handlebarand operatively connected to the left and right brakes to cause the leftand right brakes to brake the left and right endless tracksrespectively.
 2. The snowmobile of claim 1 wherein the central endlessdrive track has a rounded lateral profile.
 3. The snowmobile of claim 1,wherein the left and right endless tracks each have a rounded lateralprofile.
 4. The snowmobile of claim 1, wherein the central endless drivetrack, and left and right endless tracks each have a rounded lateralprofile.
 5. The snowmobile of claim 1, further comprising: a left motoroperatively connected to the left endless track for driving the leftendless track; and a right motor operatively connected to the rightendless track for driving the right endless track.
 6. The snowmobile ofclaim 5, wherein the left and right motors are one of electric motorsand hydraulic motors.
 7. The snowmobile of claim 1, wherein the leftbrake selectively engages an inner side of the left endless track; andwherein the right brake selectively engages an inner side of the rightendless track.
 8. The snowmobile of claim 1, further comprising: a leftswing arm operatively connecting the left track frame to the main frame;and a right swing arm operatively connecting the right track frame tothe main frame.
 9. The snowmobile of claim 8, wherein the left trackframe is pivotally connected to the left swing arm about a generallyvertical left steering axis; and wherein the right track frame ispivotally connected to the right swing arm about a generally verticalright steering axis.
 10. The snowmobile of claim 1, further comprising:footrests on left and right sides of the longitudinal centerline.